A wall is of two layers P and Q each made of different materials. Both the layers have same thickness. The thermal conductivity of the material P is twice that of Q. Under thermal equilibrium, the temperature difference across the walls is 36^(@)C. What is the temperature difference across the layer P ?

A wall is of two layers P and Q each made of different materials. Both

1.	A wall is of two layers P and Q each made of different materials. Both the layers have same thickness. The thermal conductivity of the material P is twice that of Q. Under thermal equilibrium, the temperature difference across the walls is 36^(@)C. What is the temperature difference across the layer P ?
Answer» SOLUTION :For layer P, `A=A_(1),l=l_(1),K=K_(1)` for layer Q, `A=A_(2),l=l_(2),K=K_(2)` Given `l_(1)=l_(2),A_(1)=A_(2),K_(1)=2K_(2)` We know `Q/t=KA(Deltatheta)/lrArrDeltathetaalpha1/K" "(because"here "Q/t,A&l" are same")` i.e., `(Deltatheta_(P))/(Deltatheta_(Q))=K_(Q)/K_(P)=1/2" "thereforeDeltatheta_(P)=1/3xxDeltatheta=1/3xx36=12^(@)C`